The 21st century has seen a great interest in the production of renewable energy. Harnessing wind or ocean current driven flow vibrations has been one approach for creating renewable energy, with various devices being developed to achieve such results. One such device attempts to harness wind or ocean current flow vibrations by using a bluff body having a specified surface roughness thereon, by the use of specifically sized sandpaper strips along the lengthwise span and circumference of the cylinder. Such method has several drawbacks, such as the ability of the sandpaper to lose its roughness due to the fluid flow and the requirement for the sandpaper to be located at carefully chosen points along the cylinder to produce the desired vibration amplification effects.
Further, the surface roughness method is undesirable as it fails to: a) exploit the ability of a boundary layer to naturally select and amplify flow disturbances that match its own instability frequency band and/or b) control or influence vortices after they have been shed from a bluff body. Surface roughness serves primarily to introduce random turbulent fluctuations that can trigger or accelerate the onset of flow transition. It is not a controllable flow fluctuation source that can deliver specifically tuned disturbances that can be coupled into and be amplified by the instability frequency band of the boundary layer. A need exists for an energy harvesting system that overcomes the aforementioned drawbacks.